Our objective is the development of an improved, noninvasive technique for early detection of metastases. This proposal is focused on carcinoma of the prostate and is based on two recent developments: (a) the realization that polyamine uptake by the prostate is enhanced many-fold by pretreatment with the ornithine decarboxylase inhibitor, difluoromethylornithine (DFMO) and (b) the rapid development of positron-emission transaxial tomography (PETT) scanning. In the course of this research project, we will determine the conditions for optimal uptake of polyamines by prostate derived tumors in animals. We will develop positron-emitting polyamine analogs and use them to scan tumor bearing animals. Finally, we shall conduct animal toxicity, clearance and dosimetry studies with the radiolabeled polyamines prior to using them for abdominal PETT scans in patients with prostatic cancer.